Vibration eliminator



Oct. 10, 1933. D. D. STONE VIBRATION ELIMINATOR Filed April 1, 1931 Patented Oct. 10, 1933 r g a a i UNITED STATES ATENtioFFICEj VIBRATION ELVIMINATOR Donald D. Stone, Flint, Mich., assignor to General t Motors Corporation, Detroit, Mich, a corporation of Delaware Application April 1, 1931. Serial No. 526,897 4 Claims. (clue-s The invention herein disclosed and claimed endat the left of this view. It will be underrelates to means for suppressing vibrations and stood that the'usual fly wheel (not'shown) isto particularly to balancers for dynamically supbe attached to the rearend of the shaft and pressing torsional vibrations of engine, or other that the usual engine accessories are to be driven 5 crankshafts, subjected to forces that tend to by the front end thereof. As an engine crank 60 twist them periodically. V shaft is elastic and the inertia of the flywheel v Torsional vibration balancers adapted to he te t causethe shaft to rotate at e Speed mounted elastically on the crank shafts of it will be pparent that the periodic forces d e internal combustionengines are well known and t0 the reciprocating pistons tend to twist h widely used. In this invention there is realized shaft p ywhile the elasticity of the 65 M shaft to provide for its reception;

a torsional vibration balancer susceptible. of shaft tends to restore it to its normal condition being attached to a crank shaft already in w e t thrusts 0f the p When t balance without disturbing the balance thereof; periodic Piston forces synchronize with which does not require any elongation of the bTetiOIls 0 the v g a its t a whi h may frequency, as is well known, vibrations of con- 70 be mounted on the crankshaft within the s's clerab amp itude occu p ti the housing between the fly wheel and the front front end 0f.-the shaft wh c drives the 30095- bearing; whichrnay be fabricated conveniently series, -m s' o s pp s i em e by mass production methods and readily asp y It isnotlunllsllahthelefllre, c pp y 'sembled and disassembled without the use of vibration supp d v es to t shaft a i 75 special tools. 7 w cent the front end thereof; The crank pins of The invention consists, specifically, of the -c d r engine are u a d s g d combination of a crank shaft with a ring like numerically according o their, positions m inertia mass journaled concentrically with refront to Teal, 'theiront being designated v spect to the shaft axis and surrounding a crank Crank pill ex One in Order, p

arm connecting two crank pins; said inertia s rearward, an Inthe mmass comprising two semiannular sections each bodim vChflsell illustration, the balance? carrying a spring abutment body directed radid e dhs a Whole y m 9, is u sally inward the'opposite sides of vwhich converge concentrically of and balanced with respect to :30 owa d the Center; means for holding apair of the shaft axis so as to oscillate in a plane nor' 85 springs attached respectively to opposite sides m thereto 0 oppo ely .li sp d bearing i of said abutment body} and said r k a faces formed at the opposite'ends of the double carrying on opposite edges spaced abutments crank arm 10 which connects No.1 and No; 2 adapted to oppose the abutments on said semi- Crank pins, i d ca ed r sp ctiv y y the 1111- annular section; whereby the ring-like inertia merals 11 n Pr f r ly the double 9 mass may oscillate at a given frequency about m'l nda are b nti e thecranksh'aft axis in, response to'tor'sional vithickness meas l ngi din ly of the crank brations of the shaft. t shaft axis. j i 1 In the accompanying drawing wherein like he vibratory mass: of thebalan'cer isjcom- 40 reference characters indicate like parts throughp d o WO S a i y q l l e ha v s, 95

V l 13', and 13a,"meeting end to en'dto form a conr p t a engine. crankshaft protinuous v balancer ring adapted to oscillate in vided with a balancer constructed according to bearings on the ends O the doublecrank arm this invention; 10.v .'.As shown by broken lines in Figs, 2' and 'out the several views,

Fig. 2 is a View of the balancer parts showing the dollble crank 1 l s i t rally or othe -.100

one half in section with its component parts 'Wise l i Connected a on e to the P assembled and the'other half mainly in' eleva- 11 and-at the opp sit d o th p Each tion with elements separated, and 'erid of said'arm' is grooved to form bearings and Fig. 3 is a sectional view on the line 3-3 of guides in which the'balancer ring may oscillate 50. Fig. 2, viewed in the direction of the arrows. in a plane normal to the crank shaft axis.- The 105 The crank shaft shown 'in'Fig. 1 is an eightbottom and sides of "said grooves ar'e' machined throw shaft now in use in a motor car'having on circular lines concentric with the shaft'axis, an engine with eight cylinders in tandem. or ,and the'ends of [the double crank arm may be in .line arrangement. The front end of the expanded as shown toform two equal segments v crank. shaft shown is atthe right and the rear 14 with parallel chords as illustrated infl figz ,110

. grooves referred to.

by broken lines, thus providing opposed spaces 15 between the segmental ends.

The. two semi-annular halves or sections of the balancer ring are substantially alike and may be wrought or cast in the same die or mold, or formed by the same automatic production machine." Each half 'has its endsurfa'ces 15 in one diametrical plane and is perforated through said end plane by parallel bolt holes. 16, 16a, the holes in one half registering with the holes in the other when said halves are assembled to form a complete ring. (Javities 17 are formed in each half on the convex side,

said cavities being intersected by'said'bolt holes in order to provide counter-sinks for the bolt heads 18 and nuts 18a used with bolts 19 for fastening the two halves together. In the con struction shown the bolt holes 16a are threaded to receive the threads of bolts 19 and the holes 16 are plain to receive the bolt shanksfreely.

The seetio'n's ar therefore reversed when assembledl and h'eld together by the bolts" 19 one of which engages the threaded hole in one secmen' while the other engages the threaded hole in the, other section. The'nuts 1811 are adapted to'be Iockedtoprevent unscrewingfof said bolts.

Thebalancer ring'compos ed of the two halves 13b. is formed on the inner periphery with suitable curved bearing and guiding ribs ortongues 20, adjacent the meeting ends of said halves} These ribs o rtongues r'idein the bearing and guiding. grooves previously described as torm'e d in the ends of the double crank arm 10 and segments 14 integralwith said arm. The ribs or tongues 20 and the bearing grooves may be of any suitable form in cross section, but

ee'e'h, of e urjse, should correspond in cross sectional'contourwith. the other. The said ribs or ten ues correspond approximately in circumferential extent'to the bearing and guiding e Between the ends of said ribs or tongues 20 the balancer ring is formed as if ou'taw ay interiorly to produce diametricall 'jy pposite spaces 21. Rigid with each balancer ection is a spring abutment body 22 projectin'g. radially inward from the inner side of the 'se'ction withinsaid spaces 21. The opposite sides. 23ot said abutment bodies are inclined 'equallyfconverging toward the shaft and balancer axis. Spaced-apart elevations 24 on the inclinedsi'des of the abutment body constitute abutment-bearings iio'r' the ends of leaf springs 25 converging with respect to each other toward the axis like the sides of the abutment body 22. In the embodiment illustrated the, abutment 1.2 2 are manufactured as parts separate from the balancer ring sections and are bolted to the. sectionsby boltssuch as 26'. In order topresist strains the body 22 is providedwith iebb'eted fedgesjat 2 17 and the'balancer sections withcorresponding interflttingjledges' 28 wherethe abutment body is shouldered to its seat.

xcessive strain is thereby removed from the bolts and displacement guarded against. To retam the springs 25 on opposite sides of abutment body 22 prior to end nile assembling the balancer sections on the shaft, and to prevent ,dis placement of'th'e 'springs during operation, a

spring holderor 'clip 30 is secured to the inward end of the abutment body by the head of bolt 26; Ends 31 of the spring clip 30 project at each sid'e andare cupped to receive the radiallyinwardfe'nds of springs 25, thus retaining them .in icontact with the abutment bearings 24,

Abutment elements carried on' the crank arm crank arms and secured by bolts 38.

. appended, claims.

springs 25 bear upon-them,-to avoid a sharp line contact therewith. The bars- 35 are seated in rectangular notches 37 machined in the Bearing corners or surfaces 36 bear upon springs 25 at areas between the abutment bearings 24 and on the opposite side. When the balancer is assembled on the crank shaft the springs 25 should be loaded' as represented in Fig. 2, which shows the'springs 'bent or cambered by the pressure of the abutment bearings 24 carried by the balancer ring against the ends of the springs on one side, and the opposedpressure on the other side intermediate said bearings 24 of abutments 35 carried on the crank shaft; The load ing pressures may be delicately adjusted by the use of shims. v

The plates or leaves of the'leaf springs- 25' are illustrated as rectangular, having a width approximately equal to the thickness of the balancer ring measuredlongitudinally of the shaft axis. A'sufiicient number of these plates or leaves should be assembled'ineach spring to enable it, when properly adjusted as to initial load, to impart to the balancer assembly a natural frequency of vibration adapted to balance m; the vibrations of the crankshaft vibrating at its natural frequency; 7

It will be understood-that the spring abutments 22, springs 25 and spring clips 30, will be assembled on the balancer ring sections 13 and 13d prior to assembly of the balancer on the crank shaft. The balancer ring halves are then 'moved radially toward each other, moving the tongues or ribs 20 into the grooves on the ends of the double crank arm 10. In this movement the obliquely disposed'leaf springs 25'enter readily between theabutments 35. The bolts 19 may then be inserted through the holes 16 in each section and screwed into the threaded holes 16a of the other section thus tightlybinding the two sections together and bending the springs25 to obtain the required preloading by the pressure I of abutments 35 against them. v t t The construction shown and describedis'well shaft'may be balanced before assembly therelWith of the balancer, and asthe balancer is mounted concentrically with respect tojth'e shaft and is'itself instatic and dynamic balance, no "further balancing operation is necessary after or that the terms of description shall be taken as terms of limitation, or that the scope of the invention shall be defined otherwise than by the I claim:

"1'. The combinationof a shaft, a torsional Yibration balancer ring j'ournaled thereon. concentric-with the shaft axis, said balancer ring being composed of plural ring sections adapted to be assembled around'the shaft; a pair of opposed leaf springs interposed between atleast adapted for quantity production. The crank one section of the balancer ring and the shaft, said springs having their bearing surfaces converging inward toward the shaft axis, a wedgelike body on the balancer section extending radially inward, abutment bearings for the ends of thesprings thereon, a spring retaining means secured to the balancer ring section and retaining said springs against the abutment bearings on said section, and abutments on the shaft bearing upon the sides of the springs opposite the sides which are in contact with the wedgelike body between the abutment bearings on the latter. ,v

2. A combination as defined in claim 1 in which the balancer ring is composed of two similar semi-annular sections provided with bolt holes and screw bolts adapted to draw and secure the sections together.

3. The combination of a crank shaft having plural crank pins, a double crank arm connecting two longitudinally adjacent pins, coaxial curved hearings on the ends of said arm, a

torsional vibration balancer ring journaled on said bearings, said balancer ring composed of two similar sections united substantially in a diametrical plane bisecting the crank arm longitudinally of said arm and shaft, a pair of leaf springs secured to each section, said springs converging inward toward the shaft axis, and abutment elements, carried on each side of said crank arm, bearing upon said springs.

4. A combination as defined in claim 3 in which each balancer ring'section is provided with an abutment body having sides converging inwardtoward the shaft axis, spaced abutment bearings on each side of said body, means on the ring section for retaining the springs in con- ,tact with said abutment bearings, and abutment elements on the sides of the crank arm bearing upon the springs midway between the abutment bearings on said body attached to the ring and on the opposite sides of the springs.

DONALD D. STONE. 

